Fluid coupler

ABSTRACT

A fluid coupler has a female coupler member and a male coupler member which can be connected to the female coupler member by simply inserting into the female coupler member. The female coupler member includes a first locking ball, a second locking ball and a locking ball confining ring. The confining ring has a first slanted inner surface engaging the first locking ball to partly project the first locking ball into a male coupler member receiving hole of the female coupler. The confining ring further has a second slanted inner surface and a locking ball pressing surface extending in parallel with an axis of the male receiving hole. In an insertion operation, the male coupler member first engages the first locking ball to press it against the first slanted surface, thereby axially moving the confining ring. This movement of the ring disengages the locking ball pressing surface from the second locking ball so that the second locking ball is forced by the male coupler member against the second slanted surface to move the confining ring. Upon completion of the insertion of the male coupler member, a recess formed in the outer surface of the male coupler member is radially aligned with the first and second locking balls which have been moved radially outwardly and, then, receives these locking balls thereinto, whereby the locking ball confining ring returns to its initial position wherein the first slanted surface and the locking ball pressing surface engage the first locking ball and second locking ball, respectively. Accordingly, even if an excessive pulling force is applied to the male coupler member, the locking ball pressing surface prevents the second locking ball from being moved radially to thereby positively retain the male coupler member in the female coupler member.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a fluid coupler comprising male andfemale coupler members.

[0002] A fluid coupler comprises a female coupler member and a malecoupler member adapted to be inserted into and detachably connected tothe female coupler member. The male and female coupler members aresecurely connected to each other by engagement of locking balls providedin the female coupler member with an annular locking ball receivingrecess formed on the exterior surface of the male coupler member. Toinsert the male coupler member into the female coupler member, anoperator needs to shift a locking ball confining sleeve provided on thefemale coupler member, which has confined the locking balls to aposition in which the locking balls partly project into a male couplerreceiving hole of the female coupler member for engagement with thelocking ball receiving recess, against a spring force to a positionwhere the sleeve allows the locking balls to be moved radially outwardlyby the male coupler member.

[0003] There is another type of fluid coupler in which a locking ballconfining sleeve of a female coupler member has a slanted or conicalinterior surface for engaging with locking balls. The sleeve is urged bya spring to a position where the slanted interior surface engages withlocking balls and positions them at a recess engaging position where thelocking balls engage with a locking ball receiving recess of a malecoupler member. An operator can insert the male coupler member into thefemale coupler member by simply pushing the former into the latter sothat the locking ball confining sleeve is shifted by a force applied bythe male coupler member to the slanted interior surface through thelocking balls with the spring being compressed. When the male couplermember is completely inserted into the female coupler member, thelocking ball confining sleeve is returned by the spring to an initialposition where the slanted interior surface confines the locking ballsin the locking ball receiving recess. However, this type of fluidcoupler involves a problem that the male coupler member may beaccidentally disconnected from the female coupler member. Namely, if alarge pulling force is (accidentally) applied to the male couplermember, the locking ball is urged by the male coupler member against theslanted interior surface of the sleeve and moves or displaces thelocking ball confining sleeve from its locking ball confining position.

[0004] To solve this problem, another type of fluid coupler has beendeveloped wherein a cylindrical support member is provided inside afemale coupler member such that the cylindrical support member is urgedto a position where the cylindrical support member supports lockingballs to prevent the locking balls from projecting into the male couplermember receiving hole, thereby allowing a male coupler member to beinserted into the female coupler member. When the male coupler member isinserted into the female coupler member, the male coupler member pushesthe cylindrical support member rearwards and, when the male couplemember has been completely inserted into the female coupler member, alocking ball receiving recess of the male coupler member is radiallyaligned with the locking balls, whereby a locking ball confining sleeveis shifted by under a spring force to its locking ball confiningposition, so that the locking balls are moved radially inwardly into andconfined in the locking ball receiving recess by the locking ballconfining sleeve. While this type of fluid coupler solves the problem ofaccidental disconnection, it involves another problem, namely, its size,i.e., since cylindrical support member is provided inside the femalecoupler member, the size of the female coupler member must be maderelatively large as compared with the other types of fluid couplersmentioned above.

SUMMARY OF THE INVENTION

[0005] An object of this invention is to provide a fluid coupler havinga novel fastening mechanism which enables an operator to securelyconnect a male coupler member to a female coupler member by simplyinserting the former into the latter, and which does not give rise tothe problems stated relative to the prior art fluid couplers.

[0006] Another object of this invention is to provide a coupler memberwhich may be employed in such a novel fluid coupler.

[0007] According to one aspect of this invention, there is provided afluid coupler comprising

[0008] a female coupler member; and

[0009] a male coupler member; wherein

[0010] the female coupler member comprises:

[0011] a cylindrical member including an axial through hole having afirst opening end for receiving the male coupler member and a secondopening end opposite to the first opening end, the cylindrical memberfurther including

[0012] a first radial through hole radially extending through thecylindrical member, and

[0013] a second radial through hole radially extending through thecylindrical member, the first radial through hole being positionednearer to the first opening end than the second radial through hole;

[0014] a first locking ball received in the first radial through holesuch that the first locking ball is radially movable in the first radialthrough hole;

[0015] a second locking ball received in the second radial through holesuch that the second locking ball is radially movable in the secondradial through hole;

[0016] a locking ball confining ring axially slidably disposed aroundthe cylindrical member and having an inner surface formed with

[0017] a first locking ball relieving portion enabling the first lockingball to move radially outwardly to allow the male coupler member to beinserted into the axial through hole passing the first locking ball;

[0018] a first slanted portion extending radially inwardly from thefirst locking ball relieving portion in a direction toward one of thefirst and second opening ends, the slanted portion being axially alignedand engaged with the first locking ball;

[0019] a second locking ball relieving portion 16 enabling the secondlocking ball to move radially outwardly to allow the male coupler memberto advance in the axial through hole passing the second locking ball;

[0020] a second slanted portion extending radially inwardly from thesecond locking ball relieving portion in the direction toward one of thefirst and second opening ends, the second slanted portion being axiallyaligned and engaged with the second locking ball; and,

[0021] a second locking ball pressing portion axially extending from anradially inward end of the slanted portion; and,

[0022] a spring urging the locking ball confining ring towards the otherof the first and second opening ends; and, wherein

[0023] when the male coupler member is not inserted into the femalecoupler member, the first locking ball is engaged by the first slantedportion to partly extend into the axial through hole and the secondlocking ball is engaged by the second ball pressing portion to partlyextend into the axial through hole,

[0024] when the first locking ball is engaged by the male couplermember, which is being inserted into the axial through hole from thefirst opening end, the first locking ball is forcibly moved radiallyoutwardly while moving the locking ball confining ring in an axialdirection under a force applied by the first locking ball to the firstslanted portion, thereby allowing the male coupler member to advanceinto the axial through hole,

[0025] when the male coupler member comes into engagement with thesecond locking ball after passing the first locking ball, the lockingball confining ring has been moved such that the locking ball pressingportion disengages from the second locking ball, thereby allowing thesecond locking ball to be radially outwardly to allow the male couplermember to advance further; and,

[0026] the male coupler member has an annular groove formed in the outersurface thereof which is radially aligned with the first and secondlocking balls, which have been moved radially outwardly to the first andsecond locking ball relieving portions, respectively, to receive thefirst and second locking balls thereinto so that the locking ballconfining ring is returned by the spring to an initial position whichthe sleeve takes when the male coupler member is not inserted into theaxial through hole of the female coupler member.

[0027] According to another aspect of the present invention, there isprovided a coupler member of a fluid coupler comprising:

[0028] a cylindrical member having an axial through hole; and

[0029] a valve mechanism disposed in the axial through hole of thecylindrical member;

[0030] the valve mechanism comprising:

[0031] a valve holder slidably disposed in the axial through hole thevalve holder being axially movable in the axial though hole between anopening position and a closing position;

[0032] a rotatable valve;

[0033] a pivotal shaft for pivotally supporting the rotatable valveabout a pivotal axis extending transversely with respect to the valveholder 25, 43; and,

[0034] a cam mechanism for effecting a rotational movement of therotatable valve about the pivotal axis between an opening angularposition wherein the rotatable valve allows fluid to flow through thecoupler member and a closing angular position wherein the rotatablevalve prevents fluid from flowing through the coupler member in responseto the movement of the valve holder between the opening position and theclosing position, respectively;

[0035] the cam mechanism having a cam profile hole extending through therotatable valve;

[0036] a pin arranged such that the pin extends through the cam profilehole;

[0037] the cam profile hole cooperates with the pin such that when thevalve holder is moved between the opening and closing positions, the pinengages with a wall defining the cam profile hole so that the rotatablevalve is rotated between the opening angular position and the closingangular position.

BRIEF DESCRIPTION OF THE DRAWING

[0038] These and other features, aspects, and advantages of the presentinvention will become apparent with reference to the followingdescription, claims and accompanying drawings, where

[0039]FIG. 1 is a longitudinal cross-sectional view of a fluid couplerin accordance with the present invention showing a condition in whichmale and female coupler members are disconnected from each other;

[0040]FIG. 2 is a view taken along a line A-A in FIG. 1;

[0041]FIG. 3 is a longitudinal cross-sectional view of the fluid couplershown in FIG. 1 in which the male and female coupler members areconnected to each other;

[0042]FIG. 4 is a view taken along a line B-B in FIG. 3;

[0043]FIG. 5 is a plan view of a cylindrical coupler member of the fluidcoupler shown in FIG. 1;

[0044]FIG. 6 is a view taken along a line C-C in FIG. 5;

[0045]FIG. 7 is a front view of a locking ball confining ring employedin the fluid coupler shown in FIG. 1;

[0046]FIG. 8 is a view taken along a line D-D in FIG. 7;

[0047]FIG. 9a is a view of a forward portion of the cylindrical memberof the female coupler member of FIG. 1 which is split at a position inits circumferential direction and unfolded to be flat to show apositional relationship of first and second radial through holes formedin the forward portion of the cylindrical member;

[0048]FIG. 9b is a view of a locking ball confining ring employed in thefemale coupler member which is split at a position in itscircumferential direction and unfolded to be flat to show an interiorsurface of the locking ball confining ring;

[0049]FIG. 10 is a view taken along a line E-E in FIG. 1;

[0050]FIG. 11 is a view taken along a line F-F in FIG. 3;

[0051]FIG. 12 is a longitudinal cross-sectional view of the cylindricalmember of the female coupler member;

[0052]FIG. 13 is a plan view of a valve employed in the fluid coupler ofFIG. 1 under a closing condition;

[0053]FIG. 14 is a side elevation view of the valve of FIG. 13;

[0054]FIG. 15 is a bottom view of the valve of FIG. 13;

[0055]FIG. 16 is a view taken along a line G-G in FIG. 13;

[0056]FIG. 17 is a plan view of the valve of FIG. 13 under an openingcondition;

[0057]FIG. 18 is a side elevation view of the valve of FIG. 17;

[0058]FIG. 19 is a bottom view of the valve of FIG. 17;

[0059]FIG. 20 is a view taken along a line H-H in FIG. 17;

[0060]FIG. 21 is a longitudinal cross-sectional view of the fluidcoupler of FIG. 1 in which the male coupler member is in a first stageof insertion into the female coupler member; and,

[0061]FIG. 22 is a view similar to FIG. 21 in which the male couplermember is in a second stage of insertion into the female coupler member.

DETAILED DESCRIPTION OF THE INVENTION

[0062] With reference to the accompanying drawings, there is shown afluid coupler in accordance with the present invention having a femalecoupler member 1 and a male coupler member 2. The female coupler member2 has a locking mechanism 3, as explained below, for securely connectingthe male coupler member 2 to the female coupler member 1.

[0063] The female coupler member 2 has a cylindrical member 8 including:an axial through hole 4; a plurality of first radial through holes 9which are spaced apart from each other in a circumferential direction,and which respectively radially extend through the cylindrical member 8;a plurality of second radial through holes 10 which are spaced apartform each other in a circumferential direction, and which respectivelyradially extend through the cylindrical member 8; a plurality of firstlocking balls 11 respectively received in the first radial through holes9 such that the first locking balls 11 are radially movable in the firstradial through holes 9; and, a plurality of second locking balls 12respectively received in the second radial through holes 10 such thatthe second locking balls 12 are radially movable in the second radialthrough hole 10. Further, a locking ball confining ring 13 b is axiallyslidably disposed around the cylindrical member 8.

[0064] As shown in FIG. 5 and FIG. 9a, the first radial through holes 9are positioned closer than the second radial through holes 10 to anopening end of the axial through hole 4 for receiving the male couplermember 1. The radial through holes 9 and 10 are tapered radiallyinwardly to prevent the locking balls 11 and 12 from moving out from theradial through holes 9 and 10.

[0065]FIG. 7 is a front view of a locking ball confining ring 13 b, andFIG. 8 is a view taken along a line D-D in FIG. 7. FIG. 9b is a view ofthe locking ball confining ring 13 a which is, for the sake of clarityof illustration, split at a position in its circumferential directionand unfolded to be flat to show an interior surface of the locking ballconfining ring 13 b. As will be understood from FIGS. 1, 7, 8 and 9 b,the inner surface of the locking ball confining ring 13 b has a firstannular surface or first locking ball relieving portion 14; a secondannular surface or second locking ball pressing portion 18 axiallyspaced away from the first annular surface 14, and having a diametersmaller than that of the first annular surface 14; a conical surface orslanted annular portion 15 extending between the first annular surfaceor first locking ball relieving portion 14 and the second annularsurface or second ball relieving portion 16; and, a plurality ofrecesses or second slanted portions 17 extending from a portion on thesecond annular surface 18 adjacent to the slanted annular surface 15through the annular slanted surface 15 towards the first annular surfaceor first locking ball relieving portion 14.

[0066] The locking ball confining ring 13 b is surrounded by a sleeve 13a, and is urged by a coil spring 21 forwardly to engage with the steppedportion 19 of the sleeve 13 a so that the coil spring 21 and the sleeve13 a are urged to the position shown in FIG. 1 wherein the sleeve 13 aand the locking ball confining ring 13 b are stopped by a stop ring 20.A forward end 21 a of the coil spring 21 is bent to extend radiallyinwardly and engage with a radially extending recess 22 (FIG. 9b) formedin the locking ball confining ring 13 b; and, further, slidably engageswith an axially extending groove 8 a (FIGS. 1, 9a and 12) formed in theouter surface of the cylindrical member 8 so that the locking ballconfining ring 13 b is prevented from rotating about an axis thereof,while being permitted to axially move on the cylindrical member 8. FIGS.9a and 9 b illustrate a positional relationship between the radialthrough holes 9 and 10 and the configuration of the inner surface of thelocking ball confining ring 13 b.

[0067] When the locking ball confining ring 13 b is positioned at aforward end position as shown in FIG. 1, wherein the male coupler member2 is not inserted into the female coupler member 1, or as shown in FIG.3, wherein the male coupler member 2 is completely inserted into thefemale coupler member 1, the first locking balls 11 are engaged by aradially inward end portion of the first slanted portion 15 and partlyextend into the axial through hole 4, while the second locking balls 12are engaged by the second ball pressing portion 18 and partly extendinto the axial through hole 4.

[0068] The male coupler member 2 has a cylindrical member 23 having anaxial through hole 5. The cylindrical member 23 has a portion to beslidably inserted into the axial through hole 4 which is provided on itsouter surface with a conical portion at a forward end thereof and alocking ball receiving recess 24 at a rearward portion thereof.

[0069] Upon insertion of the male coupler member 2 into the femalecoupler member 1, as the male coupler member advances in the axialthrough hole 4 towards the left end of the axial through hole 4, asviewed in FIG. 1, the conical portion of the forward end of the malecoupler member 2 first engages with the first locking balls 11 to urgethe first locking balls 11 radially outwardly, whereby the locking ballconfining ring 13 b is advanced rearwards or leftwards to allow thelocking balls to move radially outwardly and, thus, the male couplermember 2 to continue its advancement. When the conical portion of theforward end of the male coupler member 2 comes into engagement with thesecond locking balls 12, the second locking ball pressing surface 18 hasbeen moved rearwards to disengage from the second locking balls 12. Asthe male coupler member 2 is further advanced, the male coupler urgesthe second locking balls 12 radially outwardly to further move thelocking ball confining ring 13 b rearwards. When the male coupler member2 has reached a connection position where the male coupler member 2 iscompletely inserted into the female coupler member 1, the locking ballreceiving recess 24 of the male coupler member 2 is radially alignedwith the first and second radial through holes 9 and 10, therebyallowing the locking ball confining ring 13 b to be returned by the coilspring 21 to its forward position while forcibly moving the lockingballs 11 and 12 radially inwardly into the locking ball receiving recess24. As a result, the first locking balls 11 are pressed by the slantedsurface 15 and the second locking balls 12 are pressed by the secondlocking ball pressing surface 18 (FIG. 3). As will be apparent from theforegoing explanation, an operator can effect insertion of the malecoupler member 2 by holding the sleeve 3 a. As shown in the accompanyingdrawings, both the female coupler member 1 and the male coupler member 2have valve mechanisms 6 and 7 which are provided in the axial throughholes 4 and 5, respectively. Since the valve mechanisms 6 and 7 have thesame construction, detailed explanation of only the valve mechanism 6will be given below, so as to avoid unnecessary repetition.

[0070] The valve mechanism 6 of the female coupler member comprises aslidable valve holder 25 axially slidably disposed in the axial throughhole 4, and a rotatable valve 26. The slidable valve holder 25 is urgedby a coil spring 28 forwards and, when the male coupler member 2 is notinserted into the female coupler member 1, is urged against acylindrical stop 29 which is securely mounted on the interior surface ofthe axial through hole 4 by means of screw threads 30.

[0071] As shown in FIGS. 1 and 2, the slidable valve holder 25 has aforward cylindrical portion 25 a with a though hole 35, a rearwardcylindrical portion 25 b with a through hole 36, and an intermediateportion 33 with a though hole 37 positioned between the forward andrearward cylindrical portions. The intermediate portion 33 has right andleft side walls supporting the rotatable valve 26 with a pair of pivotalshafts 34, 34 which are positioned at opposite sides of the rotatablevalve 26 and aligned with each other along a pivotal axis normal to theaxis of the axial through hole 4. The rotatable valve 26 is rotatablebetween an opening angular position shown in FIG. 3, in which thethrough hole 37 is axially aligned with the through hole 35 of theforward cylindrical portion and the through hole 36 of the forwardcylindrical portion, and a closing angular position shown in FIG. 1, inwhich the through hole 37 is aligned with neither the axial through hole35 of the forward cylindrical portion nor the through hole 36 of theforward cylindrical portion, and the outer surface 26 a of the rotatablevalve sealingly engages with a sealing ring 38 provided around theopening end 35 to prevent fluid from flowing through the valvemechanism. Between the valve mechanism 6 and the cylindrical member 8,there is provided a cam mechanism for moving the rotatable valve 26between the opening angular position (FIG. 3) and the closing angularposition (FIG. 1) stated above. The cam mechanism has a cam profile hole39 extending through a portion 26 b of the rotatable valve 26 in adirection of the pivotal axis of the rotatable valve 26 and along a camprofile in a plane normal to the pivotal axis and, a pin 41 arrangedsuch that the pin extends through the cam profile hole 39 in parallelwith the pivotal axis. The cam profile hole 39 is profiled such thatwhen the slidable valve holder 25 is moved between the opening position(FIG. 3) and the closing position (FIG. 1), the pin 41 engages with awall defining the cam profile hole 39 so that the pin 41 imposes arotational force on the rotatable valve 26 to rotate the rotationalvalve between the opening angular position (FIG. 3) and the closingangular position (FIG. 1). In the embodiment illustrated in thedrawings, opposite ends of the pin 41 pass inclined elongated holes 40,40 (FIGS. 13, 14, 17 and 18) formed in the left and right walls of theintermediate portion 33 of the slidable valve holder 25 and engage witha pair of rectangular holes 42, 42 (FIGS. 10-12) formed in thecylindrical stop 29. The hole 42 vertically extends through thecylindrical stop 29 and has a rectangular cross section. An axial lengthof the cross section of the hole 42 is slightly larger than the diameterof the pin 41 to substantially prevent the pin 41 from moving in theaxial direction. When the slidable valve holder 25 is moved between theclosing position and the opening position, the walls of the inclinedelongated holes 40, 40 cooperate with the walls of rectangular holes 42,42 to slightly move the pin 41 vertically (FIGS. 10 and 11). In FIG. 1,31, 32 and 60 denote sealing rings. (Break) 19:45. (restart) 20:00

[0072] The valve mechanism set forth above is distinguishable from thetype of valve mechanism employed in a prior art fluid coupler member inwhich forward and rearward cylindrical portions of a slidable valveholder are separated from each other and a rotatable valve is held bythe forward and rearward cylindrical portions which are urged againstthe rotatable valve by spring means in such a manner that the rotatablevalve is rotated by a cam mechanism similar to that of the presentinvention as explained above. In the prior art valve mechanism, due tothe construction described above, when the slidable valve holder isaxially moved between opening and closing positions, a large frictionforce is generated between the rotatable valve and the forward andrearward cylindrical portions. In contrast, since the rotatable valve ofthe valve mechanism of the present invention is pivotally supported bypivotal shafts and, only a small friction force is generated between therotatable valve and the forward and rearward cylindrical portions, whichenables an operator to insert the male coupler member into the femalecoupler member using little force as compared with the prior art valvemechanism. The generation of only a small friction force between therotatable valve and the forward and rearward cylindrical portions alsoenable that the valve mechanism of the present invention to have longworking life.

[0073] The valve mechanism 7 of the male coupler member 2 issubstantially the same as the valve mechanism 6 of the female couplermember 1 and comprises, as main elements, a slidable valve holder 43, arotatable valve 50 with a cam profile hole 7 and a pin 59 extendingthrough the cam profile hole 7.

[0074] Although the present invention has been described in terms of aspecific embodiment, it is anticipated that alternations andmodifications thereof will no doubt become apparent to those skilled inthe art. It is therefore intended that the following claims beinterpreted as covering all such alternations and modifications as fallwithin the true spirit and scope of the invention.

What is claimed is:
 1. A fluid coupler comprising a female couplermember; and a male coupler member; wherein said female coupler membercomprises: a cylindrical member including an axial through hole having afirst opening end for receiving said male coupler member and a secondopening end opposite to said first opening end, said cylindrical memberfurther including a first radial through hole radially extending throughsaid cylindrical member, and a second radial through hole radiallyextending through said cylindrical member, said first radial throughhole being positioned nearer to said first opening end than said secondradial through hole; a first locking ball received in said first radialthrough hole such that said first locking ball is radially movable insaid first radial through hole; a second locking ball received in saidsecond radial through hole such that said second locking ball isradially movable in said second radial through hole; a locking ballconfining ring axially slidably disposed around said cylindrical memberand having an inner surface formed with a first locking ball relievingportion enabling said first locking ball to move radially outwardly toallow said male coupler member to be inserted into said axial throughhole passing said first locking ball; a first slanted portion extendingradially inwardly from said first locking ball relieving portion in adirection toward one of said first and second opening ends, said slantedportion being axially aligned and engaged with said first locking ball;a second locking ball relieving portion enabling said second lockingball to move radially outwardly to allow said male coupler member toadvance in said axial through hole passing said second locking ball; asecond slanted portion extending radially inwardly from said secondlocking ball relieving portion in said direction toward one of saidfirst and second opening ends, said second slanted portion being axiallyaligned and engaged with said second locking ball; and, a second lockingball pressing portion axially extending from an radially inward end ofsaid slanted portion; and, a spring urging said locking ball confiningring towards the other of said first and second opening ends; and,wherein when said male coupler member is not inserted into said femalecoupler member, said first locking ball is engaged by said first slantedportion to partly extend into said axial through hole and said secondlocking ball is engaged by said second ball pressing portion to partlyextend into said axial through hole, when said first locking ball isengaged by said male coupler member, which is being inserted into saidaxial through hole from said first opening end, the first locking ballis forcibly moved radially outwardly while moving said locking ballconfining ring in an axial direction under a force applied by said firstlocking ball to said first slanted portion, thereby allowing said malecoupler member to advance into said axial through hole, when said malecoupler member comes into engagement with said second locking ball afterpassing said first locking ball, said locking ball confining ring hasbeen moved such that said locking ball pressing portion disengages fromsaid second locking ball, thereby allowing said second locking ball tobe radially outwardly to allow the male coupler member to advancefurther; and, said male coupler member has an annular groove formed inthe outer surface thereof which is radially aligned with said first andsecond locking balls, which have been moved radially outwardly to saidfirst and second locking ball relieving portions, respectively, toreceive the first and second locking balls thereinto so that saidlocking ball confining ring is returned by said spring to an initialposition which said sleeve takes when said male coupler member is notinserted into said axial through hole of said female coupler member. 2.A fluid coupler as set forth in claim 1 wherein, said second slantedportion is designed so that when said second locking ball pressingportion is disengaged from said second locking ball, said second slantedportion engages with the second locking ball and, as said male couplermember advances while engaging with said second locking ball, saidsecond locking ball is forced against said second slanted portion tothereby move said locking ball confining ring axially against saidspring.
 3. A fluid coupler as set forth in claim 1 further comprising asleeve axially movably disposed around said cylindrical memberinterposing said locking ball confining ring between said cylindricalmember and said sleeve, said sleeve being designed so that, when saidsleeve is moved towards said one of said first and second opening ends,said sleeve engages with and moves said locking ball confining ringagainst said spring to a position wherein said first and second lockingball relieving portions are radially aligned with said first and secondlocking balls, respectively.
 4. A fluid coupler as set forth in claim 2,wherein said inner surface of said locking ball confining ringcomprises: a first annular surface having a predetermined axial length;a second annular surface axially spaced away from said first annularsurface and having a predetermined axial length and a diameter smallerthan that of said first annular surface; a slanted annular or conicalsurface extending between said first and second annular surfaces; and arecess extending from a portion on said second annular surface adjacentto said slanted annular surface and extending along said slanted annularsurface towards said first annular surface; said first locking ballrelieving portion being formed by said first annular surface; said firstslanted portion being formed by said conical annular surface; saidsecond slanted portion being formed by said recess; said locking ballpressing portion being formed by a portion of said second annularsurface which portion is axially aligned with said recess; said secondlocking ball relieving portion being formed by a portion of said recessthe diameter of which is the same as that of said first annular surface.5. A coupler member of a fluid coupler comprising: a cylindrical memberhaving an axial through hole; and a valve mechanism disposed in saidaxial through hole of said cylindrical member; said valve mechanismcomprising: a valve holder slidably disposed in said axial through holesaid valve holder being axially movable in said axial though holebetween an opening position and a closing position; a rotatable valve; apivotal shaft for pivotally supporting said rotatable valve about apivotal axis extending transversely with respect to said valve holder;and a cam mechanism for effecting a rotational movement of saidrotatable valve about said pivotal axis between an opening angularposition wherein said rotatable valve allows fluid to flow through saidcoupler member and a closing angular position wherein said rotatablevalve prevents fluid from flowing through said coupler member inresponse to the movement of said valve holder between said openingposition and said closing position, respectively; said cam mechanismhaving a cam profile hole extending through said rotatable valve; a pinarranged such that the pin extends through said cam profile hole; saidcam profile hole cooperates with said pin such that when said valveholder is moved between said opening and closing positions, said pinengages with a wall defining said cam profile hole so that saidrotatable valve is rotated between said opening angular position andsaid closing angular position.
 6. A fluid coupler as set forth in claim5, wherein said cam profile hole extends in a direction of said pivotalaxis and along a cam profile in a plane normal to said pivotal axis;and, said pin extends in parallel with said pivotal axis.
 7. A fluidcoupler as set forth in claim 6, wherein said pin is held in apredetermined position in a direction of said axis of said axial throughhole such that said pin is movable in a plane normal to said axis ofsaid axial through hole of said cylindrical member.
 8. A fluid coupleras set forth in claim 7, wherein said valve holder comprises a firstcylindrical portion having a first axial through hole, an intermediateportion and a second cylindrical portion having a second axial holewhich are successively arranged in that order along the axis of saidvalve holder; said intermediate portion has left and right side wallsextending between said first and second cylindrical portions torotatably hold said rotatable valve between said left and right sidewalls with a pair of pivotal shafts which are respectively positionedbetween said rotatable valve and said left and right walls along saidpivotal axis to rotatably support said rotatable valve about saidpivotal axis; said left and right side walls have inclined elongatedholes which are aligned with each other in the direction of said pivotalaxis; said pin passes through said inclined elongated holes and aresupported by said cylindrical member such that said pin is movable insaid plane normal to said axis of said axial through hole; saidrotatable valve has a through hole which is in axial alignment with saidfirst and second axial through holes to allow fluid to flowing throughsaid coupler member when said rotatable valve is in said opening angularposition and, which is out of said axial alignment with said first andsecond axial through holes when said rotatable valve is in said closingangular position; and, when said valve holder is moved between saidopening position and said closing position, said pin is slidably engagedby walls of said inclined elongated holes to thereby be moved in saidplane normal to said axis of said axial through hole of said cylindricalmember.